Venturi vs Pumped Shower Systems

[OnlyAsking...]

I have been thinking about having a loft conversion done to my 3 bed semi- now I am having to think about the bathroom and in particualar the shower. I have on the 1st floor a Monsoon 3bar twin pump, which gives me a great shower ( Very happy with this) Now I want something similar for the loft bathroom. I have looked at prices of twin 3bar neg pump and whoo £500 odd quid!! So i have looked into this Venturi system which apparantly works of the cold mains pressure and sucks hot water through with opposite pressure ( I think thats right!). So my questions are:
1. Do I really need a 3bar neg pump or can something lower be specced?
2. will adding another pump in the loft make any adverse effect on the exsisting system ( If they are both being used at the same time?)
3. Will this Venturi system work - ( I have a blue mains pipe into the property- so pressure is fairly good) what about the negative head situation?
4. what other options do I have.

Thanks in advance.

 

[ChrisR]

I doubt a venturi jobbie would suck uphill. ?

Common solution is to use a mains electric shower - the 10+kW ones are reasonable and give a backup if your water heating packs up.

You don't have to use a neg head pump if you install a switch to start it. There are two types of switch in common use - "momentary action" either pullcord or air operated.

You have to be quite careful siting pumps and organising their supplies. And HW tanks can empty awfully fast! You could use the pumped output from your existing pump (witha start switch), or use a new maybe smaller pump. You can use a shower pump to pump to basin taps even if you're only using one tap at a time - the duration isn't enough to make them overheat as long as neither tap is left running unnecessarily.